How to make a social sharing exception for Twitter / action sheet? - ios

Question

I am using the following code to call action sheet sharing in my app:
- (IBAction)sendPost:(id)sender
{
NSArray *activityItems = nil;
UIImage *appIcon = [UIImage imageNamed:#"appIcon.png"];
NSString *postText = [[NSString alloc] initWithFormat:#"LETS ASSUME THIS STRING IS LONGER THAN 140 CHARACTERS THAT TWITTER PROHIBITS BUT CAN STILL BE SHARED VIA FACEBOOK, EMAIL, TEXT"];
activityItems = #[postText,appIcon];
UIActivityViewController *activityController = [[UIActivityViewController alloc] initWithActivityItems:activityItems applicationActivities:nil];
[self presentViewController:activityController animated:YES completion:nil];
}
The problem is this: postText is longer than 140 characters, so sharing via twitter will not be possible, the character count will be -x (red number of characters you are over in order to share via twitter), my question is this: How can I make an exception so that a different message say shortPostText will be the one used when twitter is selected for sharing?
And once the sendPost action is sent I don't see a way to explicitly set a string for twitter, once you are here:
Edit: I dont understand why someone would down-vote this question, I am not asking how to make an if/else statement or how to program. This is a genuine question, that needs a genuine answer.
UPDATE: I need a work around this because this is what I get when a user tries to share via twitter in my app:
A red/negative character indicator and a non-active post button, so unless that character count goes down to 0 or less it will not allow the post to go to twitter.

Answer 1

TL;DR Use UIActivityItemSource to special case payload depending on what the user selection was.
Try this instead:
- (IBAction)sendPost:(id)sender
{
UIImage *appIcon = [UIImage imageNamed:#"appIcon.png"];
NSString *postText = [[NSString alloc] initWithFormat:#"LETS ASSUME THIS STRING IS LONGER THAN 140 CHARACTERS THAT TWITTER PROHIBITS BUT CAN STILL BE SHARED VIA FACEBOOK, EMAIL, TEXT"];
TextItemSource *itemSource = [[TextItemSource alloc] initWithString:postText previewImage:appIcon];
UIActivityViewController *activityController = [[UIActivityViewController alloc] initWithActivityItems:#[itemSource] applicationActivities:nil];
[self presentViewController:activityController animated:YES completion:nil];
}
// ------- TextItemSource.h
#interface TextItemSource : NSObject <UIActivityItemSource>
- (id)initWithString:(NSString *)string previewImage:(UIImage *)previewImage;
#end
// ------- TextItemSource.m
#implementation TextItemSource
{
NSString *_string;
UIImage *_previewImage;
}
- (id)initWithString:(NSString *)string previewImage:(UIImage *)previewImage
{
self = [super init];
if (self) {
_string = [string copy];
_previewImage = previewImage;
}
return self;
}
- (id)activityViewControllerPlaceholderItem:(UIActivityViewController *)activityViewController
{
return _string;
}
- (id)activityViewController:(UIActivityViewController *)activityViewController itemForActivityType:(NSString *)activityType
{
NSString *string = _string;
if ([activityType isEqual:UIActivityTypePostToTwitter]) {
#pragma mark TODO: do smarter thing :)
string = [_subject substringToIndex:140];
}
return string;
}
- (UIImage *)activityViewController:(UIActivityViewController *)activityViewController thumbnailImageForActivityType:(NSString *)activityType suggestedSize:(CGSize)size
{
// might want to scale image to fit suggestedSize
return _previewImage;
}
#end